Apparatus with equalizing voltage generation circuit and methods of use

ABSTRACT

A memory device includes an equalization voltage generator. The equalization voltage generator includes an oscillator and a charge pump to produce a first voltage, which may be used as an equalization voltage for pairs of complementary digit lines. The oscillator is controlled by an oscillator control signal, which is produced by a feedback and control loop of the equalization voltage generator. The feedback and control loop includes a reference generator circuit to produce a stable, internal reference signal that is clamped at a maximum reference voltage. A comparator of the feedback and control loop compares the internal reference signal with a second voltage, which is proportional to the first voltage. The comparator causes the oscillator to turn on when the second voltage is lower than the reference voltage, and causes the oscillator to turn off when the second voltage is higher than the reference voltage.

TECHNICAL FIELD

The present invention relates generally to memories, and morespecifically to apparatus and methods for equalizing voltages betweendigit line pairs within a memory device.

BACKGROUND

A dynamic random access memory (DRAM) device includes a memory cellarray. The memory cell array includes a number of memory cells, whichare arranged in rows and columns. One memory cell is positioned at theintersection of each row and column. Each row of memory cells has anassociated row line, ROW, and each column of memory cells has anassociated pair of complementary digit lines, DIGIT and DIGIT_.

At certain times (e.g., prior to a READ operation), it is desirable toequalize the voltages present on the complementary digit lines.Accordingly, the memory cell array includes an equalization circuitcoupled between each pair of complementary digit lines, which operatesto equalize the voltage on the associated pair of complementary digitlines.

In current DRAMs, each pair of complementary digit lines is equalizedusing an equalization voltage, referred to as VCCP. VCCP has a voltagelevel that is based on an externally-supplied power supply voltage, VCC.For example, VCCP may be approximately equal to VCC plus a set voltagemargin. According to some standards, VCCP=VCC+1.2 Volts (V).

VCC is prone to fluctuations. Accordingly, VCCP also is prone tofluctuations. VCCP is boosted higher than VCC to provide more robustcircuit operation in light of the VCC fluctuations. Due in part to thepower constraints, current DRAMs include NMOS gates to produce VCCP.NMOS-based designs often result in relatively large layout sizes, andaccordingly relatively larger device sizes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a simplified block diagram of a dynamic random accessmemory device, in accordance with an embodiment;

FIG. 2 illustrates a simplified block diagram of an equalizing voltagegenerator circuit, in accordance with an embodiment;

FIG. 3 is a graph illustrating an example of relative voltage levelswithin an equalizing voltage generator circuit, in accordance with anembodiment;

FIG. 4 illustrates a flowchart of a method for generating an equalizingvoltage, in accordance with an embodiment;

FIG. 5 is a top-down, elevational view of a wafer containingsemiconductor dies in accordance with an embodiment;

FIG. 6 is a simplified block diagram of an exemplary circuit module inaccordance with an embodiment;

FIG. 7 is a simplified block diagram of an exemplary memory module inaccordance with an embodiment;

FIG. 8 is a simplified block diagram of an exemplary electronic systemin accordance with an embodiment;

FIG. 9 is a simplified block diagram of an exemplary memory system inaccordance with an embodiment; and

FIG. 10 is a simplified block diagram of an exemplary computer system inaccordance with an embodiment.

DETAILED DESCRIPTION

FIG. 1 is a schematic block diagram of a dynamic random access memory(DRAM) device 100, in accordance with an embodiment. DRAM 100 is used tostore data which is accessed via input/output (I/O) lines. For contextpurposes, DRAM 100 is shown to be coupled to an external microprocessor116 for memory accessing. In alternate configurations, DRAM 100 may becoupled with additional or different types of devices (e.g., a memorycontroller or other device).

In an embodiment, DRAM 100 receives control signals from microprocessor116, such as WE*, RAS* and CAS* signals. It will be appreciated by thoseskilled in the art, based on the description herein, that additionalcircuitry and control signals can be provided, and that the DRAM of FIG.1 has been simplified to help focus on the inventive subject matter.

DRAM 100 includes one or more arrays of memory cells 102, addressdecoder 104, row access circuitry 106, column access circuitry 108,control circuitry 110, and I/O circuitry 112. In addition, in anembodiment, DRAM 100 includes one or more equalizing voltage generatorcircuits 114 (“VCCEQ generator”), operatively coupled to the columnaccess circuitry 108.

Memory cell array 102 includes a number of memory cells arranged in nrows and m columns. One memory cell is positioned at the intersection ofeach row and column. Each memory cell includes an access switch in theform of a transistor (e.g., a field effect transistor) and a storageelement in the form of a capacitor. Binary data is stored in a memorycell as a voltage across the capacitor. A voltage of approximately VCCat a first plate of the capacitor corresponds to a first binary datavalue, which is typically a 1. Conversely, a voltage of approximately 0at the first plate corresponds to a second binary data value, which istypically a 0.

Each row of memory cells has an associated row line, ROW, and eachcolumn of memory cells has an associated pair of complementary digitlines, DIGIT and DIGIT_. Each memory cell in a given row of memory cellshas a control terminal in the form of the gate of the transistor coupledto the associated row line, ROW. Each memory cell in a given column ofmemory cells has a data terminal in the form of the source terminal ofthe transistor coupled to one of the associated complementary digitlines, DIGIT and DIGIT_. Although a memory cell array 102 is describedas including complementary digit lines DIGIT and DIGIT_, one skilled inthe art will appreciate, based on the description herein, that theinventive subject matter is applicable to other memory structures andnot limited to this specific memory structure.

The memory cell array 102 includes an equalization circuit coupledbetween each pair of complementary digit lines, DIGIT and DIGIT_. Anequalization circuit operates to equalize the voltage on its associatedpair of complementary digit lines. In an embodiment, each equalizationcircuit includes an equalization transistor and a precharge circuit. Theequalization transistor has its drain and source terminals coupledbetween the complementary digit lines DIGIT and DIGIT_ and its gateterminal coupled to an equalization line.

In an embodiment, the precharge circuit includes a pair of transistors,with the drain terminals of these transistors connected to thecomplementary digit lines, DIGIT and DIGIT_, respectively. The sourceterminals of the transistors are connected to an “equalization voltage”approximately equal to VCC/2. VCCEQ generator 114 generates thisequalization voltage, in an embodiment, and the equalization voltage isreferred to herein as “VCCEQ.” The gates of the transistors are coupledto the equalization line.

In operation, an equalization circuit equalizes the voltage on itscomplementary digit lines, DIGIT and DIGIT_, to approximately theequalization voltage. To activate the equalization circuit, theequalization line is driven with a voltage approximately equal to VCC.In response to this voltage on the equalization line, the equalizationand precharge circuit transistors are turned ON. The precharge circuittransistors drive the complementary digit lines DIGIT and DIGIT_ tovoltage levels approximately equal to VCCEQ, and the equalizationtransistor assures that both the complementary digit lines are at thesame voltage level. After the complementary digit lines, DIGIT andDIGIT_, are equalized to approximately VCCEQ, the equalization line EQis driven to approximately 0 V to turn OFF the equalization andprecharge circuit transistors.

FIG. 2 illustrates a simplified block diagram of an equalizing voltagegenerator circuit 200 (e.g., VCCEQ generator 114, FIG. 1), in accordancewith an embodiment. Circuit 200 includes a feedback and control circuit210, an oscillator 206, and a charge pump 208, in an embodiment. Thefeedback and control circuit 210 includes a reference generator circuit202 (e.g., a band gap reference generator), a comparator 204, and avoltage divider circuit 226, in an embodiment.

Circuit 200 operates basically as follows. Oscillator 206 receives anoscillator control signal 218 from feedback and control circuit 210.Oscillator 206, in turn, produces an oscillator signal 220 based on theoscillator control signal 218. Charge pump 208 receives the oscillatorsignal 220 and produces a first voltage at a first node 212, where thefirst voltage is affected by the oscillator signal 220. Feedback andcontrol circuit 210 produces an internal reference voltage 216 (e.g., aband gap reference voltage) and produces the oscillator control signal218 based on the internal reference voltage 216 and the first voltage.Production of the internal reference voltage 216 and production of theoscillator control signal 218 are described in more detail below.

The first voltage, which is carried by a first node 212 of circuit 200,is referred to as a “first node voltage” or “V₂₁₂.” In an embodiment,the first node voltage is an equalizing voltage, VCCEQ, for digit linepairs within a DRAM device. In other embodiments, the first node voltagemay be used for other purposes. Although the first node voltage may bereferred to below as VCCEQ, this example is not meant to be limiting.

As mentioned previously, the first node voltage, at node 212, isproduced by charge pump 208. A main purpose of charge pump 208 is toproduce a voltage that may be higher than an external voltage, VCCX. Forexample, charge pump 208 may be capable of producing an output voltageat node 212 that exceeds 1.5 V, even though the circuit may be suppliedwith an external voltage, VCCX, of 1.0 V or less. As the belowdescription will indicate, circuit 200 is able to produce a stable VCCEQthat is higher than the external voltage. Accordingly, the circuit mayconsume less power than other circuits.

Charge pump 208 produces the first node voltage in response anoscillator signal 220, which charge pump 208 receives from oscillator206. When oscillator 206 is on (i.e., it is producing oscillator signal220), the voltage produced by charge pump 208 increases. Accordingly, inan embodiment, VCCEQ increases. When oscillator 206 is off, the voltageat node 212 decreases. In an embodiment, the voltage decrease occurs atleast in part due to a current flow through divider circuit 226. Thevoltage may decrease due to current flow through other portions of thecircuitry (not shown) as well (e.g., when VCCEQ is used to equalizeDIGIT and DIGIT_).

Oscillator 206 is turned on and off in response to the oscillatorcontrol signal 218, which is provided by comparator 204. In anembodiment, comparator 204 includes an operational amplifier. Comparator204 produces the oscillator control signal 218 in response to acomparison between a reference voltage 216 and a second node voltagepresent at a second node 214 of circuit 200. The voltage present atsecond node 214 is referred to as a “second node voltage” or “V₂₁₄.”

In an embodiment, the second node voltage is a fraction of the firstnode voltage (i.e., the voltage present at first node 212). The relativevalues of the first node voltage and the second node voltage areprimarily affected by the ratio between the voltage divider circuit'sresistors 222, 224 (referred to respectively as R1 and R2), in anembodiment, as follows: $\begin{matrix}{V_{212} = {V_{214}\left( {1 + \frac{R_{1}}{R_{2}}} \right)}} & {{Equ}.\quad 1}\end{matrix}$

For example, but not by way of limitation, V₂₁₄ may be used as anequalization voltage, VCCEQ, for a memory cell array. When in steadystate, it may be desired to maintain VCCEQ at a pre-defined level,regardless of the value of VCC. For example, even if VCC is <<1 V, itmay be desired to maintain VCCEQ at a pumped up value of approximately1.5 V. According to Equ. 1, above, and assuming that R₂=433 R₁, thenV₂₁₄ approximately equals 0.8×V₂₁₂. Accordingly, if V₂₁₂=VCCEQ≈1.5 V,then V₂₁₄=1.2 V, which is the same as the reference voltage level atnode 216 (e.g., the band gap reference voltage).

Circuit 200 may have the effect of immunizing V₂₁₂ (e.g., VCCEQ) fromfluctuations in the supply voltage, VCC. In an embodiment, this isachieved by comparing V₂₁₄ (which is directly affected by V₂₁₂) with asteady reference voltage 216, which is produced by reference generatorcircuit 202. In an embodiment, reference generator circuit 202 is a bandgap reference (BGR) circuit or a voltage clamping circuit.

Reference generator circuit 202 receives V₂₁₂, and produces an outputvoltage 216 that tracks V₂₁₂, but which is clamped at a “maximumreference voltage.” For example, in an embodiment, the circuit 202 maybe designed to produce a maximum reference voltage equal to V₂₁₄ (e.g.,1.2 V) when V₂₁₂ has reached the target VCCEQ (e.g., 1.5 V).Accordingly, the maximum reference voltage may approximately equal 1.2V, in the given example.

FIG. 3 is a graph illustrating an example of relative voltage levelswithin an equalizing voltage generator circuit, in accordance with anembodiment. FIG. 3 may be best understood by simultaneously referring tothe circuit of FIG. 2, as well. The graph of FIG. 3 represents anexample of relative V₂₁₂ and V₂₁₄ voltage levels (indicated alongvoltage axis 304) over time (indicated along time axis 302). V₂₁₂ isrepresented by graph line 306 and V₂₁₄ is represented by graph line 308.

Initially, the circuit is off. During a power up time 310, theoscillator 206 is turned on, and thus charge pump 208 begins to ramp upV₂₁₂ 306. Simultaneously, V₂₁₄ 308 also ramps up in proportion to V₂₁₂306. When comparator 204 determines that V₂₁₄ 308 approximately equalsthe maximum reference voltage 316 (i.e., by comparing the voltage atnode 214 with the voltage at input 216), comparator 204 indicates thatV₂₁₂ 306 has reached the target voltage 314 (e.g., target VCCEQ).Accordingly, at time 312, when V₂₁₂ approximately equals target voltage314, and V₂₁₄ 308 approximately equals the maximum reference voltage316, comparator 204 provides an oscillator control signal 218 to turnoff oscillator 206.

As mentioned previously, after oscillator 206 turns off, V₂₁₂ 306 willbegin to decrease, as indicated by segment 320 of V₂₁₂ 306. As V₂₁₂ 306decreases, V₂₁₄ 308 also decreases, as indicated by segment 322 of V₂₁₄308. Eventually, V₂₁₄ 308 will reach a voltage 324, which causescomparator 204 to determine that V₂₁₂ is sufficiently less than themaximum reference voltage 316. At that time 326, comparator 204 willprovide an oscillator control signal 218 to turn oscillator 206 back on.This will cause charge pump 208 to again increase V₂₁₂ 306, and thusV₂₁₄ 308. When V₂₁₄ 308 again approximately equals the maximum referencevoltage 316, comparator 204 will cause oscillator 206 to turn off. Thison-off oscillator cycling will continue (e.g., throughout period 318 andthereafter) until the circuit is powered down.

As the previous paragraph indicates, a certain amount of hysterisisexists in the oscillator control loop. In other words, duringsteady-state operations, V₂₁₂ 306 and V₂₁₄ 308 vary within relativelysmall voltage ranges that are proximate to the target output voltage 314and the maximum reference voltage 316, respectively. In an embodiment,the voltage range for the target output voltage is 0.9% VCCEQ-1.1%VCCEQ. The range for the maximum reference voltage is proportionallyless than the range for the target output voltage. In variousembodiments, the voltage ranges may be wider or narrower than theabove-given range. In addition, in various embodiments, these voltageranges may exist above, below, or surrounding the target output voltage314 and the maximum reference voltage 316.

Although relatively small output voltage fluctuations exist within theabove ranges, these fluctuations are not affected by the lesspredictable fluctuations that may exist with the external supplyvoltage, VCCX. Accordingly, using embodiments of the inventive subjectmatter, a process/voltage/temperature (“PVT”) invariant VCCEQ may begenerated regardless of more PVT affected VCCX fluctuations. Further,using embodiments of the inventive subject matter, circuits may bedesigned without the thick NMOS processes. Layout sizes may thus bereduced.

FIG. 4 illustrates a flowchart of a method for generating an equalizingvoltage, in accordance with an embodiment. The method begins, in block402, when power is initially supplied to an equalizing voltage generatorcircuit (e.g., VCCEQ generator 114, FIG. 1). In an embodiment, power issupplied from an external source, VCCX, which may have voltage levelsfrom less than 1 V to higher than 3 V. As mentioned previously,embodiments of the invention may provide a stable VCCEQ at a voltagelevel that is higher than VCCX, and which is not affected by normalfluctuations in VCCX.

When power is initially supplied to the circuit, an oscillator signalproduced by an oscillator (e.g., oscillator 206, FIG. 2) is used todrive a charge pump (e.g., charge pump 208). The charge pump produces avoltage at an output node (e.g., node 212) of the circuit. In anembodiment, the voltage at the output node is used as an equalizingvoltage for complementary digit lines in a DRAM.

In block 404, a reference generator circuit (e.g., circuit 202) producesa reference voltage (e.g., at 216), which is approximately equal toand/or proportional to the output voltage of the charge pump, exceptthat the reference generator circuit clamps the reference voltage at amaximum reference voltage level. In an embodiment, the maximum referencevoltage level is less than a target output voltage (e.g., VCCEQ).

In block 406, a comparator (e.g., comparator 204) compares the referencevoltage with a second voltage (e.g., at node 214), which represents adivided version of the voltage produced by the charge pump (e.g., atnode 212). While the second voltage is sufficiently less than thereference voltage, as determined in block 408, the comparator producesan oscillator control output signal that causes the oscillator to be inan “on” state, in block 410. If the second voltage is substantiallyequal to or sufficiently greater than the reference voltage, thecomparator produces an oscillator control output signal that causes theoscillator to be in an “off” state, in block 412. In another embodiment,the comparator does not cause the oscillator to turn off when thereference voltage and the second voltage are substantially equal, butwaits until the second voltage is sufficiently greater than thereference voltage before turning the oscillator off.

The method then iterates as shown in FIG. 4, by continuously comparingthe reference voltage and the second voltage, and producing anoscillator control signal accordingly. The method ends when power isremoved from the circuit.

As recognized by those skilled in the art, memory devices of the typedescribed herein are generally fabricated as an integrated circuitcontaining a variety of semiconductor devices. The integrated circuit issupported by a substrate. Integrated circuits are typically repeatedmultiple times on each substrate. The substrate is further processed toseparate the integrated circuits into dies as is well known in the art.

FIG. 5 is a top-down, elevational view of a wafer 500 containingsemiconductor dies 510 in accordance with an embodiment. A die is anindividual pattern, typically rectangular, on a substrate that containscircuitry, or integrated circuit devices, to perform a specificfunction. At least one of the integrated circuit devices includes anequalizing voltage generator (e.g., VCCEQ generator 114, FIG. 1),embodiments of which are disclosed herein.

A semiconductor wafer will typically contain a repeated pattern of suchdies containing the same functionality. Die 510 may contain circuitryfor the inventive memory device, as discussed above. Die 510 may furthercontain additional circuitry to extend to such complex devices as amonolithic processor with multiple functionality. Die 510 is typicallypackaged in a protective casing (not shown) with leads extendingtherefrom (not shown) providing access to the circuitry of the die forunilateral or bilateral communication and control.

FIG. 6 is a simplified block diagram of an exemplary circuit module 600in accordance with an embodiment. As shown in FIG. 6, two or more dies610, 612, 614 (e.g., die 510, FIG. 5) may be combined, with or withoutprotective casing, into circuit module 600 to enhance or extend thefunctionality of an individual die. Circuit module 600 may be acombination of dies representing a variety of functions, or acombination of dies containing the same functionality.

Some examples of a circuit module include memory modules, devicedrivers, power modules, communication modems, processor modules, andapplication-specific modules and may include multilayer, multichipmodules. Circuit module 600 may be a subcomponent of a variety ofelectronic systems, such as a clock, a television, a cellular or radiocommunication device (e.g., cell phone, pager, etc.), a desktop,handheld or portable computer, an automobile, an industrial controlsystem, an aircraft, an automated teller machine, and others. Circuitmodule 600 will have a variety of leads 602 extending therefrom andcoupled to the dies 610, 612, 614 providing unilateral or bilateralcommunication and control.

FIG. 7 is a simplified block diagram of an exemplary memory module 700,which is an embodiment of a circuit module. Memory module 700 generallydepicts a Single Inline Memory Module (SIMM) or Dual Inline MemoryModule (DIMM). A SIMM or DIMM is generally a printed circuit board (PCB)or other support containing a series of memory devices. While a SIMMwill have a single in-line set of contacts or leads, a DIMM will have aset of leads on each side of the support with each set representingseparate I/O signals.

Memory module 700 contains multiple memory devices 710, 712, 714 (e.g.,memory device 100, FIG. 1) contained on support 716, the numberdepending upon the desired bus width and the desire for parity. Memorymodule 700 may contain memory devices on both sides of support 716.

Memory module 700 accepts a command signal from an external controller(not shown) on a command link 720 and provides for data input and dataoutput on data links 730, 732, 734. The command link 720 and data links730, 732, 734 are connected to leads 740 extending from the support 716.Leads 740 are shown for conceptual purposes and are not limited to thepositions shown in FIG. 7.

FIG. 8 is a simplified block diagram of an exemplary electronic system800 containing one or more circuit modules 802, 804, 806 (e.g., circuitmodule 600, FIG. 6) in accordance with an embodiment. Electronic system800 generally contains a user interface 810. User interface 810 providesa user of the electronic system 800 with some form of control orobservation of the results of the electronic system 800. Some examplesof user interface 810 include a keyboard, pointing device, monitor, andprinter of a computer; a keypad, speaker, microphone, and display of acommunication device; a tuning dial, display, and speakers of a radio;an ignition switch and gas pedal of an automobile; and a card reader,keypad, display, and currency dispenser of an automated teller machine,among other things. User interface 810 may further describe access portsprovided to electronic system 800. Access ports are used to connect anelectronic system to the more tangible user interface componentspreviously exemplified.

One or more of the circuit modules 802, 804, 806 may include one or morememory devices, in accordance with various embodiments, and/or one ormore processors providing some form of manipulation, control ordirection of inputs from or outputs to user interface 810, or of otherinformation either preprogrammed into, or otherwise provided to,electronic system 800. As will be apparent from the lists of examplespreviously given, electronic system 800 may contain certain mechanicalcomponents (not shown) in addition to circuit modules 1600 and userinterface 810. It will be appreciated that the one or more circuitmodules 802, 804, 806 in electronic system 800 can be replaced by asingle integrated circuit. Furthermore, electronic system 800 may be asubcomponent of a larger electronic system.

FIG. 9 is a simplified block diagram of an exemplary memory system 900,which is an embodiment of an electronic system. Memory system 900includes one or more memory modules 902, 904, 906 (e.g., module 700,FIG. 7) and a memory controller 916. Memory controller 916 provides andcontrols a bidirectional interface between memory system 900 and anexternal system bus 920. Memory system 900 accepts a command signal fromthe external bus 920 and relays it to the one or more memory modules902, 904, 906 on a command link 930. Each memory module 902, 904, 906may include one or more memory devices 910, 912, 914 (e.g., memorydevice 100, FIG. 1). Memory system 900 provides for data input and dataoutput between the one or more memory modules 902, 904, 906 and externalsystem bus 920 on data links 940, 942, 944.

FIG. 10 is a simplified block diagram of an exemplary computer system1000, which is a further embodiment of an electronic system. Computersystem 1000 includes one or more processors 1010 and one or more memorysystems 1012 (e.g., system 900, FIG. 9) housed in a computer unit 1014.Computer system 1000 is but one example of an electronic systemcontaining another electronic system (e.g., memory system 900) as asubcomponent. Computer system 1000 optionally includes or is coupled tovarious user interface components. Depicted in FIG. 10 are a keyboard1020, a pointing device 1030, a monitor 1040, a printer 1050, and a bulkstorage device 1060. It will be appreciated that other components may beassociated with computer system 1000, such as modems, device drivercards, additional storage devices, etc. It will further be appreciatedthat the processor 1010 and memory system 1012 of computer system 1000may be incorporated on a single integrated circuit.

In the foregoing description of the embodiments, reference is made tothe accompanying drawings, which form a part hereof and show, by way ofillustration, specific embodiments in which the inventive subject mattermay be practiced. These embodiments are described in sufficient detailto enable those skilled in the art to practice the inventive subjectmatter.

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat any arrangement that is calculated to achieve the same purpose maybe substituted for the specific embodiments shown. It is to beunderstood that other embodiments may be utilized, and that process ormechanical changes may be made, without departing from the scope of theinventive subject matter. Many adaptations of the disclosed embodimentswill be apparent to those of ordinary skill in the art, based on thedescription herein. Accordingly, this application is intended to coveradaptations or variations of the invention. It is manifestly intendedthat this invention be limited only by the following claims andequivalents thereof.

1. A circuit comprising: an oscillator to receive an oscillator controlsignal and to produce an oscillator signal based on the oscillatorcontrol signal; a charge pump, electrically coupled to the oscillator,to receive the oscillator signal and to produce a digit lineequalization voltage at a first node, wherein the digit lineequalization voltage is affected by the oscillator signal; and afeedback and control circuit, electrically coupled to the first node, toproduce an internal reference voltage, and to produce the oscillatorcontrol signal based on the internal reference voltage and the digitline equalization voltage.
 2. The circuit of claim 1, wherein thefeedback and control circuit comprises: a reference generator circuit toproduce the internal reference voltage.
 3. The circuit of claim 2,wherein the reference generator circuit includes a band gap referencecircuit, to receive the digit line equalization voltage and to clamp theinternal reference voltage at a voltage level that is less than a targetvalue for the digit line equalization voltage.
 4. The circuit of claim2, wherein the feedback and control circuit further comprises: acomparator to make a comparison between the internal reference voltageand a second voltage that is affected by the digit line equalizationvoltage, and to produce the oscillator control signal based on thecomparison.
 5. The circuit of claim 4, wherein the comparator is toproduce a first oscillator control signal that causes the oscillator toturn on when the second voltage is less than the internal referencevoltage, and the comparator is to produce a second oscillator controlsignal that causes the oscillator to turn off when the second voltageapproximately equals or is greater than the internal reference voltage.6. The circuit of claim 4, wherein the feedback and control circuitfurther comprises: a voltage divider circuit, to produce the secondvoltage as a fraction of the digit line equalization voltage.
 7. Anequalized supply voltage generating circuit of a memory devicecomprising: an oscillator to receive an oscillator control signal and toproduce an oscillator signal based on the oscillator control signal; acharge pump, electrically coupled to the oscillator, to receive theoscillator signal and to produce a first voltage at a first node,wherein the first voltage is affected by the oscillator signal, andwherein the first voltage is usable as an equalized supply voltage formemory cells within a memory cell array; and a feedback and controlcircuit, electrically coupled to the first node, to produce an internalreference voltage, and to produce the oscillator control signal based onthe internal reference voltage and the first voltage.
 8. The circuit ofclaim 7, wherein the feedback and control circuit comprises: a referencegenerator circuit to produce the internal reference voltage; a voltagedivider circuit, to produce a second voltage as a fraction of the firstvoltage; and a comparator to make a comparison between the internalreference voltage and the second voltage, and to produce the oscillatorcontrol signal based on the comparison.
 9. The circuit of claim 8,wherein the reference generator circuit includes a band gap referencecircuit, to receive the first voltage and to clamp the internalreference voltage at a voltage level that is less than a target valuefor the first voltage.
 10. The circuit of claim 8, wherein thecomparator is to produce a first oscillator control signal that causesthe oscillator to turn on when the second voltage is less than theinternal reference voltage, and the comparator is to produce a secondoscillator control signal that causes the oscillator to turn off whenthe second voltage approximately equals or is greater than the internalreference voltage.
 11. A memory device, comprising: an array of memorycells; and an equalized supply voltage generating circuit that includes:an oscillator to receive an oscillator control signal and to produce anoscillator signal based on the oscillator control signal, a charge pump,electrically coupled to the oscillator, to receive the oscillator signaland to produce a first voltage at a first node, wherein the firstvoltage is affected by the oscillator signal, and wherein the firstvoltage is usable as an equalized supply voltage for memory cells withinthe array of memory cells, and a feedback and control circuit,electrically coupled to the first node, to produce an internal referencevoltage, and to produce the oscillator control signal based on theinternal reference voltage and the first voltage.
 12. The memory deviceof claim 11, wherein the feedback and control circuit comprises: areference generator circuit to produce the internal reference voltage; avoltage divider circuit, to produce a second voltage as a fraction ofthe first voltage; and a comparator to make a comparison between theinternal reference voltage and the second voltage, and to produce theoscillator control signal based on the comparison.
 13. The memory deviceof claim 12, wherein the comparator is to produce a first oscillatorcontrol signal that causes the oscillator to turn on when the secondvoltage is less than the internal reference voltage, and the comparatoris to produce a second oscillator control signal that causes theoscillator to turn off when the second voltage approximately equals oris greater than the internal reference voltage.
 14. The memory device ofclaim 1 1, further comprising: a row access circuit coupled to the arrayof memory cells; a column access circuit coupled to the array of memorycells; and an address decoder circuit coupled to the row access circuitand the column access circuit.
 15. A dynamic random access memorydevice, comprising: an array of memory cells; a row access circuitcoupled to the array of memory cells; a column access circuit coupled tothe array of memory cells; an address decoder circuit coupled to the rowaccess circuit and the column access circuit; and an equalized supplyvoltage generating circuit, coupled to the array of memory cells, whichincludes: an oscillator to receive an oscillator control signal and toproduce an oscillator signal based on the oscillator control signal, acharge pump, electrically coupled to the oscillator, to receive theoscillator signal and to produce a first voltage at a first node,wherein the first voltage is affected by the oscillator signal, andwherein the first voltage is usable as an equalized supply voltage formemory cells within the array of memory cells, and a feedback andcontrol circuit, electrically coupled to the first node, to produce aninternal reference voltage, and to produce the oscillator control signalbased on the internal reference voltage and the first voltage.
 16. Thedynamic random access memory device of claim 15, wherein the feedbackand control circuit comprises: a reference generator circuit to producethe internal reference voltage; a voltage divider circuit, to produce asecond voltage as a fraction of the first voltage; and a comparator tomake a comparison between the internal reference voltage and the secondvoltage, and to produce the oscillator control signal based on thecomparison.
 17. The dynamic random access memory device of claim 16,wherein the comparator is to produce a first oscillator control signalthat causes the oscillator to turn on when the second voltage is lessthan the internal reference voltage, and the comparator is to produce asecond oscillator control signal that causes the oscillator to turn offwhen the second voltage approximately equals or is greater than theinternal reference voltage.
 18. A semiconductor die, comprising: asubstrate; and an integrated circuit supported by the substrate andhaving a plurality of integrated circuit devices, wherein selected onesof the integrated circuit devices include an equalized supply voltagegenerating circuit that includes: an oscillator to receive an oscillatorcontrol signal and to produce an oscillator signal based on theoscillator control signal, a charge pump, electrically coupled to theoscillator, to receive the oscillator signal and to produce a firstvoltage at a first node, wherein the first voltage is affected by theoscillator signal, and wherein the first voltage is usable as anequalized supply voltage for memory cells within the array of memorycells, and a feedback and control circuit, electrically coupled to thefirst node, to produce an internal reference voltage, and to produce theoscillator control signal based on the internal reference voltage andthe first voltage.
 19. The semiconductor die of claim 18, wherein thefeedback and control circuit comprises: a reference generator circuit toproduce the internal reference voltage; a voltage divider circuit, toproduce a second voltage as a fraction of the first voltage; and acomparator to make a comparison between the internal reference voltageand the second voltage, and to produce the oscillator control signalbased on the comparison.
 20. The semiconductor die of claim 19, whereinthe comparator is to produce a first oscillator control signal thatcauses the oscillator to turn on when the second voltage is less thanthe internal reference voltage, and the comparator is to produce asecond oscillator control signal that causes the oscillator to turn offwhen the second voltage approximately equals or is greater than theinternal reference voltage.
 21. An integrated memory circuit,comprising: a substrate; and an integrated circuit supported by thesubstrate, wherein the integrated circuit includes an equalized supplyvoltage generating circuit that includes: an oscillator to receive anoscillator control signal and to produce an oscillator signal based onthe oscillator control signal, a charge pump, electrically coupled tothe oscillator, to receive the oscillator signal and to produce a firstvoltage at a first node, wherein the first voltage is affected by theoscillator signal, and wherein the first voltage is usable as anequalized supply voltage for memory cells within the array of memorycells, and a feedback and control circuit, electrically coupled to thefirst node, to produce an internal reference voltage, and to produce theoscillator control signal based on the internal reference voltage andthe first voltage.
 22. The integrated memory circuit of claim 21,wherein the feedback and control circuit comprises: a referencegenerator circuit to produce the internal reference voltage; a voltagedivider circuit, to produce a second voltage as a fraction of the firstvoltage; and a comparator to make a comparison between the internalreference voltage and the second voltage, and to produce the oscillatorcontrol signal based on the comparison.
 23. The integrated memorycircuit of claim 22, wherein the comparator is to produce a firstoscillator control signal that causes the oscillator to turn on when thesecond voltage is less than the internal reference voltage, and thecomparator is to produce a second oscillator control signal that causesthe oscillator to turn off when the second voltage approximately equalsor is greater than the internal reference voltage.
 24. An electronicsystem comprising: a processor; and an integrated memory circuit coupledto the processor, wherein the integrated memory circuit includes: anoscillator to receive an oscillator control signal and to produce anoscillator signal based on the oscillator control signal, a charge pump,electrically coupled to the oscillator, to receive the oscillator signaland to produce a first voltage at a first node, wherein the firstvoltage is affected by the oscillator signal, and wherein the firstvoltage is usable as an equalized supply voltage for memory cells withinthe array of memory cells, and a feedback and control circuit,electrically coupled to the first node, to produce an internal referencevoltage, and to produce the oscillator control signal based on theinternal reference voltage and the first voltage.
 25. The electronicsystem of claim 24, wherein the feedback and control circuit comprises:a reference generator circuit to produce the internal reference voltage;a voltage divider circuit, to produce a second voltage as a fraction ofthe first voltage; and a comparator to make a comparison between theinternal reference voltage and the second voltage, and to produce theoscillator control signal based on the comparison.
 26. The electronicsystem of claim 25, wherein the comparator is to produce a firstoscillator control signal that causes the oscillator to turn on when thesecond voltage is less than the internal reference voltage, and thecomparator is to produce a second oscillator control signal that causesthe oscillator to turn off when the second voltage approximately equalsor is greater than the internal reference voltage.
 27. A method forgenerating an equalized supply voltage for an array of memory cells, themethod comprising: an oscillator receiving an oscillator control signaland producing an oscillator signal based on the oscillator controlsignal; a charge pump receiving the oscillator signal and producing afirst voltage at a first node, wherein the first voltage is affected bythe oscillator signal, and wherein the first voltage is usable as anequalized supply voltage for the array of memory cells; and a feedbackand control circuit producing an internal reference voltage, andproducing the oscillator control signal based on the internal referencevoltage and the first voltage.
 28. The method of claim 27, whereinproducing the internal reference voltage comprises a reference generatorcircuit of the feedback and control circuit receiving the first voltageand clamping the internal reference voltage at a voltage level that isless than a target value for the first voltage.
 29. The method of claim27, wherein producing the oscillator control signal comprises: producinga second voltage as a fraction of the first voltage; making a comparisonbetween the internal reference voltage and the second voltage; andproducing the oscillator control signal based on the comparison.
 30. Themethod of claim 29, wherein producing the oscillator control signalcomprises: producing a first oscillator control signal that causes theoscillator to turn on when the second voltage is less than the internalreference voltage; and producing a second oscillator control signal thatcauses the oscillator to turn off when the second voltage approximatelyequals or is greater than the internal reference voltage.
 31. The methodof claim 27, further comprising equalizing complementary digit lineswithin the array of memory cells using the first voltage.